The World Economic Forum’s 2010 trade index report found that Cambodia slipped to No. 102 of 126 countries, down nine places from 2009.
Chevron, Bunge, ConocoPhillips, General Dynamics, General Electric, Johnson and Johnson, IBM, and JP Morgan will all take part.
Seeing Gulf Coast oil spill, environmental and other groups in Cambodia say the country needs to do more to safeguard its environment.
Cambodia is considering increasing formal diplomatic relations with Iran, including establishing an embassy in the capital Tehran.
The Economist Intelligence Unit estimated in April the riel would depreciate an average 1.3 percent in 2010 and 2011.
Officials say a lack of confidence from both local and foreign investors has stymied construction recovery.
Cambodia insists it has been transparent in managing state revenue.
Shareholders last week voted in favor of more transparency in payments to host countries like Cambodia.
Two men were accused of incitement in an ongoing land dispute between villagers and a powerful ruling party senator.
It is not uncommon for companies to pay bonuses for concessions here, but what happened to that money remains unknown.
Nearly 2.2 million people visited Cambodia last year. About 1 million of those came from Thailand, either by air or road.
Cambodia has similar problems of debt, tax collection and corruption.